Telephone system



Feb. 19 1924.

- 1,484,134 c. w. KECKLER v TELEPHONE SYSTEM Filed March 27. 1918 CHARLES W. KECKLER, OF NEW new annsnmnssienon TO wns'rnanntncrnrc COMPANY, INCOREORATED, OFHEW YORK, N. '55., A GOBBOEATIQN OF NEW YORK,

TELEPHONE SYSTEM. 1 i I T 0 all "whom it may concern:

Be it known that I, Crnienns' N. KE KLER, a citizen of the United States, residing at Newark, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone sys' tems and more particularly to signaling means therefor and to trunking arrangements between an intercommunicating telephone system and an exchange system.

One object of the present invention is to enable a single piece of apparatus to be used as a signal when included in a signaling circuit and also as an impedance means on establishment of the talking connection of the apparatus with which it is associated. In accordance with this feature, a signal, operable on direct current, is associated with a telephone set for normal signaling operation, and arranged for inclusion in the talking circuit of such set under certain conditions to serve as an impedance means for talking current supplied to such set on establishment of talking connection there.-.

with.

Another object is to provide anew and improved trunking arrangement between one or more local telephone stations and an outside line or exchange, in which a trunk line can be held during conversation and also during the temporary disconnection or the transfer ofa call from one local station to another without giving a disconnect signal at the exchange. In accordance with this feature of the invention, a trunk circuit, provided with two ends inductively connected, extends from the local station to the distant station or exchange and is provided with a bridging connection across one end of the trunk line and with means, operated by telephonic association of a local station with the other end of the trunk line, to con trol the bridging connection.

Another object is to provlde a telephone system in which the signal of a local station '7 i i p i 1 Application filed March 27, 1918. Seria1.I\To. 224t,'925. f,

operating circuit therefor will be established in the usual operation of calling such station even though the called station be already connected with another local station'or with the trunk'line. J 1 1 Other objects and features of the invention will appear from a consideration ofthe following description.

, In the drawing, which represents an embodiment of the invention as applied to an intercommunicating system provided with a trunk connection to a common battery exchange, three stations of the intercommunicating system are shown, together with a trunk line extending therefrom touan exchange at which the jack 10 and answering signal 11 of the trunk areilocated.

The intercommunicating stations are each provided with a transmitter ,12, receiver 18, Y a

hook switch 14, and signal 15, whichin addition to servlng as a slgnal acts as animpedance means through which talking cur.-

rent is supplied to its respective station'when thelatter is called byand secures a talking which enable interconnection between ,suchf stations, and such stations .asare equipped i for trunk service also have a trunk key T, as well as a retaining keyR if they are to be able to prevent the operation: of the disconnect signal at the exchange on the transfor of a trunk call to another station of the system. I v

The keys with the exception of the home keys H. have three positions: the normal position, as shown; the way-down position, which is the signalingv position for all but keys It and T and in which position the upper pair and the lower pair of contacts are engaged. and where the third contact en; gages the bus bar 16; and an intermediate position whichis the same as the way-down position except that there is no engagement with-the bus'bar 16.. The home keys H need have only a normal and an intermediatepo: sitionsince it is not necessary that anyof the contacts thereof engage thebus bar 16 under any conditions. A; spring-held-locking plate '17 serves. to hold any key, once de-j pressed, against release .until another key is operated, but permits any key depr essed to way-down positlon to assume its intermedn ate position as soon as pressure thereon is removed.

To illustrate the operation of the system,

i assume that station A. desires to communiatin interrupts its circuit and is 'deener- V gize but the armature on retraction immediately closes this circuit and the armature is" again attracted, thereby again opening its circuit. This action will continue so long as keyB'is maintained in signaling positi'on or until station B responds by removtion of usual manner. 7

ing the receiver from "theswitchhook 14. The' key B on'being released from signaling position assumes itsintermediate position and the receiver at station A,having been removed from the switchhook thereat, is placed in communication with B upon the latter removing his receiver and depressing his home key H to intermediate position. A circuitv is thus comileted, extending from talking battery 27, conductors 28 and 29, upper winding signal 15 at B, lower alternate contacts of switchhooks 14, conductor 30, first and second contacts of key H at B, conductors '31 and 32, upper alternate contacts of switchhook 14, receiver 13, transmitter 12, conductors 33 and 34, fourth and 7 third contacts of key H, conductor 23, middle alternate contacts of switchhook 14, conductor 35, lower winding of signal 15, and conductors 25 and 26, to the other side of battery 27. Station A is connected in parallel. with this circuit beginning at conductor 30, and extending over line conductor 36, conductor 37,-first and second contacts of key B at station A, conductor 38, upper alternate contacts of switchhook 14, receiver 13, transmitter 12, conductor 39, fourth and third contacts of key B, and conductors 21 and 22 to conductor 23. The windings of the signal 15 at the called station B thus serve :as impedance means for talking currentlsupplied to the connected stations A and B and while the armature of the signal 15 at the called station will'be attracted under hese conditions, it will not vibrate, inasm'iich'asa short ('lIClllt lS provided about'the armature contact upon the removal of the receiver at B. V This short circuit extends frOIn tlieI connection of the conductors 23 and-24g 'throngh'the middle contacts of the switc'hhook 14. and conductor 35 to the juncthe armature connection therewith, Conversation can now take place in the It is often desirable that a party at one local station already connected with another local station be apprised of any attempt by a third local station to connect with the first station while thus connected, and in the circuit arrangement shown the calling party would receive such an indication. To illustrate: Assume C calls A. Depressing key A at station C completes a circuit through the lower winding of signal 15 at station A; this circuit extending from battery'18, conduc-' and conductor 46 to the connection of the armature therewith. The single tap givenby the signal 15 serves to indicate to A that another local station desires to obtain connection withstation A. As soon as key A at station Q is released from signaling position the signaling circuit is opened and the signal at station A returns to its normal position.

When A and Bcomplete conversation they will restore their receivers to their respective switchhooks, thereby opening the talking circuit therebetween at the switch hooks, while the key B at station A and key H at station B will be released to normal position on depression of another key at its respective station, thus restoring the apparatus associated with stations A and B to normal condition.

Referring now to the trunking operation of the system,'assume that station A desires to make a trunk call. The trunkkey T thereat is depressed to intermediate posi-' tion. A circuit is therebyestablished extending from local trunk talking battery 47, right-hand winding of relay 4'8 (also-serving as an impedance means), conductor 49,

trunk conductor 50, conductor 51, fourth and fifth contacts of key T at station A, conductor 39, transmitter, receiver, and upper contacts of switchhook, conductor 38, sec end and first contacts of key T,conductors 52, 53 and 54, and left-hand winding of relay! 48 to the other side'of battery. Y Con-- densers 55 and 56 are arranged in the respective trunk conductors 50 and 53 to pre' vent flow f direct current from the battery '47 to the exchange, but the operation of relay 48 closes a circuit to bridge a relay;

57 across the exchange side of the conductors 50 and 53 and completes a circuit to actuate the answering al 11 at the exchange, This circuit ex ends from sianal ing battery 58, normal ring contact of jack 10, conductor 53, armature and alternate contact of relay 48, conductor 59, winding ott relay 57, conductor 50, normal tip conwilt of jack 10, and signal 11 to the other side of battery 58. Signal 11 is thereby ac tuated and the exchange operator responds by plugging in at the -jack 10 in the usual manner, thereby disconnecting the answer ing signal 11 from the trunk line. The operator extends the line to the called party in the usual manner, and conversation takes place between station A and the called party in the usual manner, talking battery (not shown) being supplied to the exchange end of the line on the operators answeringthe call. The condensers 55, 56 permit the passage of the fluctuating voice currents between the exchange and intercommunicating ends of the trunk line and enable local'talking battery 47 to be supplied at the intercommunicating end of the trunk, thereby providing more uniform and improved transmission than where talking current for intercommunicating stations connected with the trunk line is supplied from the exchange.

Should an outside line call the trunk associated with the intercommunicating system, the operator would plug into the jack 10 and apply signaling current to operate the trunk signal 60, which signal is preferably located in proximity to a local stationv charged with the duty of answering trunk calls. On perceiving the operation of the signal 60, the party, for example, at station A, removes the receiver and depresses the trunk key T to intermediate position, thereby establishing talking connection with the trunk line, but without operating the signal 11, since this is disconnected on the operator plugging intothe jack 10. It station A is the desired station, conversation now takes place in the usual way, but if the calling party desires to talk with station l), the party at A retains the receiver off the switchhook and depresses retaining key R to way-down position, there'- by completing an energizing circuit for a holding relay 61. This circuit extends from battery 18, conductors 26 and 62, resistance 71. winding of relay 61, conductors 63 and 64, third contact of ey R, bus bar 16-, and conductors 20 and 19 to the other side of battery 18. Relay- 61 operates, completing a holding circuit for itself extending from battery 18, conductors 26 and 62, resistance 71, winding left-hand armature and alternate contact of relay- 61, conductor 70, lefthand armature and alternate contact-0t relay 57 (still energized) and conductors and 19 to the other side of battery 18. The operation of relay 61 also provides a circuit connection for the relay 57, to bridge it across the trunk conductors independent of the alternate contact of relay 48. This connection extends from conductor 50, winding lay 61 todeenergize the latter.

of relay 57, conductors 59 and 66, right hand armature and alternate contact of lay 61 to conductor53. 1 The depression of key B returns key normal position, and in order to prevent any possibility of relay 48 being deenergized and opening the circuit of relay 57, thus giving a disconnect signal at the exchange before the r lay 61 could be operated to complete the holding circuit for relay 57 {the first, second, fourth and fifth'contacts ot key T are multipled respectively to the same contacts of key R; Relay 57 is thus retained energized and efiectually prevents a disconnect signal being given at the exchange -at this time. The party at A new depresses key B, thereby releasing key R and opening the circuit of relay 48, whose armature thereupon returns to normal. This does not afl'ect relay 57 as its alternate circuit has already been completed, nor will it affect relay 61 since its holding circuit is independent of the key R. i

' The party at A now obtains connection with B as explained for an ordinary local call, informs him that he is wanted on the trunk line, and then replaces the receiver upon the switchhook. B now depresses trunk'key T to way-down position, thereby releasing home key H (depressed in connecting with A), completing a circuit to operate the relay 48 as described for station A, and also completing a short circuit about the re- This short circuit extends from battery 18, conductors 19 and 67. bus bar 16, third contact of key T at station B, and conductors 68 and-69,

resistance 71 (which prevents too great flow of current over this circuit), and con' ductor 62 to the other side of battery; Deenergization of relay61 opens its holding circuit and also the alternate circuit of the relay 57 which relay remains energized,

however (the relay 48 having operated before the short-circuiting of relay 61), and

prevents a disconnect'signal bein given at t? i the exchange. The apparatus is now in the same condition as if B had answered the trunk call directly and conversation can now take place between B and the calling party.

Should any local station attempt to secure connection with another-local station which is already connected with thetrunk line, a

single tap will. be given by the signal 150i the latter local station to informtheparty thereat of such a call, but'the other local station will notobtain atalking connection since the home button H of any stationconnected with. the trunk line is in normal-posi:v tion. 4

(3n completion of trunk conveix ationthe parties would restore their receivers to their respec ive switc hooks, therebyin the usual me. dee'nern g relay 48, and turn opening the brid ng connection betweenthe exchange end of the trunk through the relay 57. The disconnect signal at the exchange Ell ing circuit in said circuit as an impedance (not shown) is therebyoperated to'indicate that conversation had been completed and the operator withdraws her plug (not shown) from the jack 10, which connects the answering signal 11 across the line for future operation and restores the entire system to 'normal'position.

What is claimed is:

;1. In a telephone system in combination, a plurality of subscribers stations, a telephone set at each or" said stations, a source of talking current, an electromagnetic signal individual to each of said sets operated by direct current and having two windings, each interposed between a different pole of the source of talking current and a telephone set to serve as impedance means for talking current on establishment of a talking circuit between telephone sets of said system, and means to establish a talking circuit between telephone sets of said system including the two windings of the signal individual to one of the telephone sets connected by said talkmeans for talking current supplied to said connected sets,

2. in a telephone system, in combination, a plurality of subscribers stations, a telephone set at each of said stations, a source of talking-current, an electromagnetic signal individual to each of said sets operated by direct current having two windings, each interposed between a diiterent pole of the source of talking current and a telephone set to'serve as impedance means for talking current on' establishment of a talking connection between telephone sets of. said system, means to operate the signal at a called station, and means to establish a talking circuit between telephone sets of said system including the two windings oi" thesignal individual to called station of the telephone sets connected by said talking circuit in said circuit as an impedance means for current supplied to saidconnection. r

I 3. In a telephone system, in combination,

a plurality of subscribers stations, a telephone set at each of sa d stations, a source,

r of talking current, an electroma netic signal individual to each of said sets operated by direct current and having two windings, each interposed between a different pole of the source oftalking current and telephone setto serve as impedance means for talking current on establishment of a talkmg connection between telephone sets ot' said system, means to establish a talking circuit between telephone sets of said system in-v cludingthe two windings of a signal indi-' to one of the telephone sets connected Sllid talking circuit in said circuit as an im edance means for current su plied to talking current on establishment of a talking connection between telephone sets of said system, means to operatethe signal at a called station, means to establish a talkmg circuit between telephone sets of said system including the two windings of the signal individual to a called station of the telephone sets connected by said talking circuit in said circuit as an impedance means for current supplied to said connection, and means to limit the signaling actuation of such signal subsequent to its inclusion in said talking circuit.

5. In a telephone system, in combination, a plurality of subscribers stations, a telephone set at each of said stations, a source of talking current, an electromagnetic direct current signal at each of said stations having two windings, each interposed between a diiierent pole of the source of talking current and a telephone set to serveas impedance means for talking current supplied to its station and said signal also including an interrupting device, an operating circuit for said signal interrupted by said device, means to establisha talking circuit between telephone sets of said system including said source of current and the two windings of the signal of one oi the sets connected there by in said talking circuit as an impedance rent and a telephonesetyan operating cir-r cuit for said signal, said signal including an interrupting device to open said circuit on energization of said signal and to close said circuit on deenergizationthereof, means to establish a talking circuit between a pair of the telephone sets of said system including the source of current in the two wind-' ings of the signal of: one of the sets connected bysaid' talking circ .it therein as impedance means, and a shuntconnection' about the interrupting device of the signal on establishment of said talking circuit.

7. In a telephone system, in combination, a telephone station, a telephone set at said station, a pair of line conductors comprising two ends inductively connected for association with said station, a normally open bridging connection across one end or said pair, a relay having a plurality of windings and controlling said bridging connection, a

local source of current, a second bridging connection across the other end of said pair including said source of current and having a relay winding intermediate said source or" current and each of said conductors, and a circuit including said relay and source of current established on telephonic association of said telephone set with said other end of said pair to'operate said relay.

8. In a telephone system, in combination, a telephone station, a telephone set at said station, a pair of line conductors comprising two ends inductively connected for asso ciation with said station, a normally open bridging connection across one end or said pair, means operated on telephonic association of said telephone set with the other end of said pair to control said bridging connection, an alternative bridging connection to said first mentioned connection, and means to control said alternative bridging connection independent of the means controlling said first mentioned bridging connection.

9. In a telephone system, in combination, a telephone station, a telephone set at said station, pair of line conductors comprising two ends inductively. connected for association with said station, a normally open bridging connection across one end of said pair, means operated on telephonic association of said telephone set with the other end of said pair to control said bridging connection, an alternative bridging connection to said first mentioned connection, means to control said alternative bridging connection independent of the association of telephone set with said other end of said pair, and means to disable, the means to establish said alternative connection incidental to subsequent tele- ,phonic connection of said telephone set with said other'end of said pair.

10. In a telephone system, in combination, a plurality of telephone stations, a telephone set at each of said stations, a pair of line conductors comprising two ends inductively connected for association with any of said stations, a normally open bridging connection across one end of said pair, means operated on telephonic association of one of said telephone sets with the other end of said pair to control said bridging connection, an alternative bridging connection, means to control said alternative connection independent of the association'ot any of said telephone setswith said other end of said pair, and means to disable the means to establish said alternative connection incident to sub sequent telephonic connection of any of said telephone sets with saidother end of said pair. I

11. in a telephone system, combination, a telephone station, a telephone set at said station, pair 01 line conductors comprising two ends inductively connected'i or association with said station, a normally open bridging connection across one end of said pair, means operated on telephonicassociation of 'l telephone set with the other end of said "a r, to control said bridging connection, an

J. In a telephone system, in combination,

plurality of telephone stations, a telephone set at each of said stations, a pair of line conductors comprising two ends inductively c nnected tor association with any of said tion across one end of saidvpair, means open ated on telephonic association of one of said te ephone sets with the other end of said pair to control said bridgingconnection, an alternative bridging connection, electromagnetic means to control said alternative connection independent of the means controlling'said iii-st mentioned connection, and means to short-circuit said electromagnetic means incidental to subsequent connection of one of said telephone sets with said other end of said line. 4

13. In a telephone system, in combination, a plurality of telephone stations, a telephone set at each of said stations, a pair of'line conductors comprising two ends inductively connected for association with said station, a normally open bridging connection across one ad of said pair, a relay included in said connection and operated on establishment thereof, switching means at each of said stations, electromagnetic means controlled by said switching means to establish said bridgn connection, and a locking circuit for said electromagnetic means established on operation of said relay.

14. In a telephone system, in combination, a plurality of telephone stations, a telephone set at each of said stations, a pair of line conductors comprising two ends inductively connected for association with said station, a normally open bridging connection across one end of said pair, a relay included in said connection and operated on establishment thereof, switching means at each of said stations, electromagnetic means controlled by rations, a normally openbridging connec- I said switching means to establish said bridg-- tromagnetic means established on operation electromagnetic means.

of said relay, and means operated incident to si'lhsequent association Ci a telephone set with said other end of said pair to disable said 15. In a telephone system, in combination, a plurality of telephone stations, a telephone set at each of said stations, a pair of line conductors comprising two ends inductively connected for association withsaid station,

a normally open bridging connection across one end of said pair, a relay included in said connection and operated on establishment hereof, switching means at each of said stations, electromagnetic means controlled by said switching means to establish said bridging connection, a locking circuit for said electromagnetic means established on operation of said relay, means operated incident to subsequent association of a telephone set with said other end of said pair to disable said electromagnetic means, a second bridging connection acrossthe same end of said pair as the first connection, and means to establish said second connection incident to subsequent association of the telephone set with said other end of said pair.

16. In a telephone system, in combination, a plurality of stations, a telephone set at each of said stations, a local signal at each of said stations, means to telephonically connect two of said stations, and means to operate the local signal of one of said connected stations during telephonic connection thereof incidental to the calling of such station by another of said stations without destroying the efiective telephonic connection of the two connected stations.

17. In a telephone system, in combination, a plurality of stations, a telephone set at each of said stations, a local signal at each of said stations, means to telephonically connect a calling and a called one of said sta tions together, and means to operate the local signal of the calling of said connected stations during telephonic connection thereof incidental to the calling of said calling station by another of said stations without destroying the effective telephonic connection of the two connected stations.

18. In a telephone system, in combination, a plurality of local stations,a telephone set at each of said stations, a local signalat each of said stations, the coils ofwhich signal form an integral part of a telephone circuit when one of said stations calls and'isconnected with another station telephonically, a trunk line extending to one of said staa tions, means to telephonically connect such station with said trunk line, and means whereby the local signal of such station may be operated during telephonic connection at each ofsaid stations, a local signal at a trunk line adapted to be connected with;

one of said stations, means to telephonically connect said station with said line, a talking circuit established between said station and said line on operation of said connect-' ,mg means, and a signaling circuit'distmct from said talking circuit to operate the local signal at said station during talking connectlon of said station and line, whereby inter:

ference between said: circuits is prevented.

20. In a telephone system, in combination,

a plurality of local stations, a telephone set at each of said stations, a trunk line leading to the central oliice station adapted to be telephonically connected with one of'sai'd stations, a signal circuit, means at other of said local stations adapted to complete said circuit, a local signal at such station adapt ed to be included in said circuit and including a circuit interrupting means normally operable to interrupt said circuit during actuation of said circuit completing means, and means to provide a shunt path about said interrupting means on connection of such station with said trunk linewhereby said interrupting device is inoperative to interrupt said signal circuit on actuation of said circuit completing means during connection of such station with said trunk line.

In witness whereof, I hereunto subscribe iny name this 18th day ofMarch, A. D., 

